This invention relates generally to the art of waste disposal, and more specifically to devices and systems for relieving, or evacuating, aerosol cans of pressurized propellant gases and residue contents in preparation for disposing or recycling the cans.
Pressurize aerosol cans, and other pressurize containers, have widespread usage in homes and industry. It has long be recognized that improper disposal of such containers constitutes a safety hazard in that excessive external heat and/or pressure can cause them to explode if they have not been relieved of internal pressure. Similarly, release of contents, both propellant gases and dangerous residue materials, from such containers often damages the environment.
Due to these hazards, the Environmental Protection Agency (EPA), an Agency of the US government, regulates disposal of pressurized containers as well as their contents for industries. These regulations mandate that certain businesses and industries must puncture all pressurize containers prior to their disposal. Further, these regulations require that certain contents of pressurize containers be captured and disposed of in particular manners. Depending upon the natures of such contents, disposal methods can involve permanent disposal through incineration, landfills or other means; treatment and permanent disposal; treatment and recycling; and treatment and reclamation for a new use. An example of reclamation would be recovering a solvent contained in waste paint for use as a fuel. But, whichever disposal method is used, the EPA requires many industries to relieve the pressure in pressurize containers prior to transporting them for disposal.
In addition to the above requirement of the EPA, many states within the United States and countries outside the United States have requirements similar to, or even stricter than, those of the EPA. For example, California closely regulates release of gases into the atmosphere. In this respect, California considers some propellants used in aerosol cans to be contaminants, particularly when they contain small aerosolized particles of materials, such as insecticides, paints, and the like, which were in the aerosol cans.
There have been a number of prior-art devices suggested for piercing pressurized containers described in U.S. and foreign patents. Probably, the most widely used of such devices is described in U.S. Pat. No. 5,265,762 to Campbell et al. This Campbell et al. patent describes a puncturing device for aerosol containers which includes an elongated tubular housing having male threads at a second end for being screwed into a first, or large, bung-plug hole (bung hole) of an off-the-shelf drum, such as a 15, 30 or 55 gallon drum. An aerosol can to be disposed of is inserted in a first opening at a first end of the cylindrical housing, nozzle-end-first, until a shoulder of the aerosol can engages a sealing shoulder in the elongated tubular housing. A puncturing device mounted on the side of the housing is driven through the housing to puncture the aerosol can above its nozzle valve (which is directed downwardly), but below the sealing shoulder of the elongated tubular housing. Propellant gas and residue material from the aerosol can are driven by pressure of a propellant gas in the can out of a second end opening of the housing into the drum. The sealing shoulder prevents the propellant gas and residue from retro-movement toward the first end opening of the housing (which opens to the environment) and ensures that these materials go into the drum.
The Campbell et al. (U.S. Pat. No. 5,265,762) also describes an aerosol-container reliever system which further includes a filter screwed into a second, or small bung opening, of the drum for filtering propellant gases escaping from the second bung opening of the drum so as to clean such escaping gaseous vapors of atmosphere-harmful materials.
Other patents which describe devices and systems relating to the system described in Campbell et al. (U.S. Pat. No. 5,265,762) include U.S. Pat. Nos.:
3,358,883 to Loe; 3,828,976 to Sidelinker; 3,926,340 to Tygenhof; 4,349,054 to Chipman et al.; 4,407,341 to Feldt et al.; 5,114,043 to Collins, Jr.; 5,181,462 to Isaac; 5,271,437 to O=Brien et al.; 5,284,997 to Spearman et al.; 5,309,956 to Hajma; 5,365,982 to O=Neill.
Although some of the devices and systems described in these various prior-art patents have some advantages, there are several existing shortcomings which these prior-art devices and systems do not overcome.
One problem not adequately addressed by these prior-art patents is that propellant gases can escape from most of their housings once punctured aerosol cans have been removed from the housings. There is no adequate structure described in the prior art for correcting this.
One of the above-mentioned patents, namely Isaac (U.S. Pat. No. 5,181,462), describes a system (see FIG. 6 of that patent) in which a can to be punctured is pressed against a valve stem for opening a valve through which propellant gases and residue is expelled. In the device of Isaac, once the can is removed, the valve is biased to close and prevent escape of collected fluids. However, the valve described in Isaac is relatively expensive to construct, is difficult to integrate with the rest of Isaac's housing, and has a valve seat which greatly restricts evacuation flow of propellant fluids and residue.
Thus, it is an object of this invention to provide a valve on a housing for an aerosol can puncturing device which prevents backflow of propellants and residue but which can be easily integrated into the housing, is relatively inexpensive to construct, is effective in use, does not unduly restrict flow of propellants and residue, and can be used when the housing is screwed into a drum bung hole.
Yet another difficulty with the prior-art described above is that none of the devices described therein has an adequate mechanism for holding a can while the can is being pierced. In this regard, a number of these prior-art patents do describe mechanisms for holding cans while they are pierced; for example, Campbell et al. (U.S. Pat. No. 5,265,762) describes a Aforce-applying apparatus,@ which is basically a plate mounted on a shaft longitudinally slidable relative to the housing. The plate can be pressed downwardly against a can and the shaft can than be clamped in position relative to the housing so that the plate holds the can tightly against the sealing shoulder. Although this mechanism functions reasonably well, it is difficult for many people to manipulate it to apply a sufficiently great and constant force against the can for adequately driving the can squarely against the sealing shoulder. Thus, in some cases, once the can has been pierced below the sealing shoulder, propellants and residue have escaped pass the sealing shoulder, around the can directly into atmosphere. Thus, it is another object of this invention to provide an inexpensive and easy-to-construct holding mechanism for tightly holding a can in a housing while the can is pierced. It is also an object of this invention to provide such a holding mechanism which positively centers the can being held, thereby ensuring that it is held straight so that its shoulder is flush, or square, on the sealing shoulder of the housing.
Still another shortcoming of the devices and systems described in the above-cited prior-art is that they do not provide a portable kit for evacuating aerosol cans without unduly contaminating the environment. In this respect, Campbell et al. (U.S. Pat. No. 5,265,762) does disclose a puncturing device for aerosol containers which is sold as a kit with a filter, as mentioned above, with the puncturing device and filter to be mounted on a drum at first and second bung holes thereof and propellant gas passing through the drum and filter to atmosphere. However, such a portable filter mounted on a drum has been found to be inadequate for preventing contamination in many cases. Therefore, it is yet another object of this invention to provide a portable aerosol-container evacuating kit which includes a filter which can be coupled with a second bung hole of a drum which adequately cleans propellant gases evacuated from aerosol cans which is effective in use, uncomplicated in structure, relatively inexpensive to construct, and relatively easy to mount and use.